// 2025/10/20
// 路径总和

/**
 * Definition for a binary tree node.
 * struct TreeNode {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode() : val(0), left(nullptr), right(nullptr) {}
 *     TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 *     TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
 * };
 */
class Solution {
public:
    bool hasPathSum(TreeNode* root, int targetSum) {
        if(root == nullptr)
            return false;
        if(root->left == nullptr && root->right == nullptr)
            return root->val == targetSum;
        
        targetSum -= root->val;
        if(root->left && hasPathSum(root->left, targetSum))
            return true;
        if(root->right && hasPathSum(root->right, targetSum))
            return true;
        return false;
    }
};